Affective distress intolerance is defined as the inability to endure negative emotional experiences, specifically by engaging in maladaptive behaviors to temporarily alleviate the experience, and is theorized to be a key functional dimension underlying a wide range of psychopathology, such as eating disorders, self-injury, and substance abuse. Individuals with poor affective distress tolerance engage in behaviors meant to achieve temporary relief from high levels of negative affect, despite the potential long-term negative consequences engendered by these behaviors. As such, affective distress intolerance is a key theoretical target for change in the development and evaluation of promising new psychological treatments. However, nearly all examinations in the current literature have relied on self-report measurement for investigating the functional dimension of affective distress intolerance as both a maintenance factor and potential treatment mechanism. Reliance on self-report measures is problematic, as it likely produces highly inaccurate data, potentially due to bias, unwillingness to report on maladaptive behavior, poor insight, and/or poor recall. These issues highlight the need to utilize multimodal measurement techniques to more objectively identify maintenance factors of psychopathology and to evaluate treatment targets and mechanisms. However, there are currently no validated behavioral paradigms or measures that tap specifically into affective distress tolerance. Binge eating, a key symptom of eating disorders (EDs) across diagnoses, is a particularly good example of a maladaptive behavior hypothesized to be driven by affective distress intolerance. Given the very low efficacy of extant treatments fo EDs, development and validation of a behavioral measure of affective distress tolerance would allow for the valid identification of affective distress tolerance as a maintenance factor (i.e., target identification), and evaluation of mechanisms and moderators of promising treatments (i.e., target engagement and validation). The proposed Ruth L. Kirschstein National Service Award (NRSA) is a 2-year program of research and training focused on the validation of a behavioral measure of affective distress intolerance and use of novel assessment methods (e.g., ecological momentary assessment; EMA) to examine the moderating role of distress tolerance in the maintenance of binge eating. The current study aims to (1) test the hypothesis that a behavioral paradigm of affective distress tolerance will demonstrate sound psychometric properties; (2) test the hypothesis that individuals with binge eating (n=40) will demonstrate poorer affective distress tolerance than those without (n=40); and (3) test the hypothesis that affective distress tolerance will moderate the relation between negative affect and subsequent binge episodes, as measured by EMA. The NRSA will provide the candidate with the training and research experiences necessary to pursue an independent research career, with special expertise in measure development and psychometrics, laboratory-based measurement, EMA, and theoretical exploration of cross-diagnostic maintenance factors, especially as they relate to eating pathology.